Division of Matrix‐ and Fracture‐Type Shale Oils in the Jiyang Depression and Their Differences

Abstract

AbstractThis study discussed the division of matrix‐ and fracture‐type shale oils in the Jiyang Depression, and proposed the concept of fracture development coefficient. The fracture development coefficient is defined as the ratio of fault throw to the distance between a shale oil well and the nearest fault. Based on CO2 content, state of water, oil production and logging response of shale oil formations, the classification of shale oils was established, Le., a fracture‐type shale oil well has a fracture development coefficient greater than 0.2, while a matrix‐type one has a fracture development coefficient less than 0.2. Furthermore, the key control factors of matrix‐ and fracture‐type shale oil enrichment were analyzed using typical anatomical and statistical methods. For matrix‐type shale oil enrichment, these factors are lithofacies, total organic carbon (TOC), shale porosity and abnormal pressure; for fracture‐type shale oil enrichment, they are lithofacies, extent of fracture development, and abnormal pressure. This study also first described the differences between matrix‐ and fracture‐type shale oils. The results provide reference for the exploration of terrestrial faulted basins in eastern China.